This invention relates to a system for preparing numerical control information, particularly a system that permits numerical control information to be prepared without requiring that an operator possesses a high level of skill.
In numerically controlled machining it is required that a variety of numerical control (hereinafter NC) information be entered in a numerical control device so that a machine tool employing the NC device may machine a workpiece drawn out on a blueprint. An increase in the productivity of a numerically controlled machine tool could be expected if it were possible for an ordinary individual to enter the NC information quickly and accurately in a simple manner. Ordinarily the NC information for the control of a machine tool is stored by punching it in a paper NC tape or by writing it in a portable bubble cassette memory. The numerical control device, while reading the NC information several blocks at a time from the NC tape or from the portable bubble cassette memory, processes the information and sends commands to the NC machine tool which responds by performing the prescribed machining operation.
The NC information stored on the NC tape or in the portable bubble cassette memory is prepared by manual calculation or by using a computer. The manual calculation method used, for example, in the numerical control of a contour, proceeds in the following manner for a simple two-dimensional figure. First, the diagram on the blueprint is divided into blocks of line segments and arcs, and information relating to each of the blocks is assembled line-by-line in the form of a list or table, thereby creating a process sheet. Information is prepared in accordance with the process sheet and is then stored sequentially on the NC tape or in the portable bubble cassette memory. In accordance with the computer method, input language for automatic programming is used to prepare a part program for each workpiece, an appropriate medium is used to input the part program in an apparatus that prepares numerical control information through use of a computer, the apparatus prepares the numerical control information automatically on the basis of the input data, and the numerical control information is stored on an NC tape or in the portable bubble cassette memory. Both of these methods for preparing NC information are disadvantageous because an individual not accustomed to such practice would have to remember how to prepare process sheets or would have to memorize the input language for automatic programming. An individual not having received such training would find it almost impossible to prepare the NC information. Furthermore, even an individual skilled in NC information preparation finds the task a troublesome one when adopting the conventional methods described above. Hence there is great demand for a system that would enable an NC machining procedure to be input and processed quickly, simply and accurately by an operator of ordinary skill. Until now a novel system of this type has not been realized in the art.